Measurement Sensitivity Improvement in Tapping-Mode Atomic Force Microscopy Through Bi-Harmonic Drive Signal
Macrander, Albert T.
This article presents a novel method to improve the measurement sensitivity and reduce impact forces in tapping-mode atomic force microscopy by reshaping the tip trajectory. A tapping drive signal composed of two harmonics is used to generate an oscillating trajectory with a broader valley compared to the typical sinusoidal trajectory. The wide broad valley reduces the velocity of the tip in the vicinity of the sample and allots a greater portion of each period in the vicinity of the sample. Numerical simulations show that this results in decreased impact force and increased sensitivity of the cantilever oscillation to changes in tip-sample offset. Experimental results demonstrate an increase in image sharpness and decrease in tip wear using the bi-harmonic driving signal.
M. Loganathan et al., "Measurement Sensitivity Improvement in Tapping-Mode Atomic Force Microscopy Through Bi-Harmonic Drive Signal," Review of Scientific Instruments, American Institute of Physics (AIP), Jan 2011.
The definitive version is available at http://dx.doi.org/10.1063/1.3648103
Mechanical and Aerospace Engineering
Keywords and Phrases
Atomic Force Microscopy; Signal Generators; Silicon; Atomic Force Microscopes; Image Analysis; Materials Properties; Scanning Probe Microscopes; Image Sensors; Instability Analysis; Second Harmonic Generation
Article - Journal
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